Report from

Movies via computerAbstract or complex concepts are difficult to communicate.

Often they are best grasped visually-particularly through animated films.But making such movies has been tedious and expensive.

At Bell Laboratories, therefore, we are experimenting with moviesby photographing computer-controlled cathode-ray tubes.

Not only is this more efficient than traditional methods, for manykinds of movies, but the computer can sometimes reveal

motions and shapes which are otherwise concealed in masses of data.Here are examples of our work.

"Force, Mass, and Motion," an

educational film by F. W. Sinden, showshow gravity-like forces and inertia affectbodies with various initial velocities.This interplay is hard to visualize, butis clear on the screen. It produces thecurves in the upper picture, one framefrom the movie. This film, costly withconventional animation, is inexpensivehere because the computer makespictures by solving equations.

In one sense, the computer movie isa "perfect laboratory"; it demonstratesexactly how our mathematical modelswould behave and helps us to look forimperfections in our experimentalapparatus when we do go ahead inthe laboratory.The lower picture is another frame

from the movie. Here the program wasslightly altered to view the system froma reference frame moving with thecenter of mass. The apparently complexcurves traced by the bodies in theupper picture turn out in the lower oneto be ellipses moving together linearly.

K. C. Knowlton's BEFLIX (Bell flicks)is a computer program whose input is adescription of the desired movie in thelanguage of the filmmaker: CAMERA,DISSOLVE, ZOOM. Its output is amagnetic tape containing an encodingof pictures. These are subsequentlydisplayed on a cathode-ray tube wherethey are photographed.The BEFLIX picture is a rectangular

array of dots; the intensity of each canvary through eight levels. The film-maker can tell BEFLIX that lines orarcs should be drawn, areas '"painted"various shades of gray, displayedshapes moved in various directions,and the like. There is an assortment ofletter sizes and faces for titling.The frames below were produced in

the BEFLIX language. The first is froma movie describing BEFLIX itself. Thesecond is from a movie about a newprogramming language produced atBell Laboratories. In this film, animated"bugs" demonstrate how informationis moved around in the computer.

In this newmethod of ani-mation, bothfilm motionand display onthe tube canbe controlledautomaticallyby informationon a magnetictape.

A movie by E. E. Zajac demonstratesthe effects of gravity in keeping acommunications satellite facing theEarth. Satellite motion is described bycomplicated differential equations.They can be solved on a computer, butthe resulting list of numbers is almostincomprehensible. In the movie, how-ever, the dynamics of satellite motion-stability, orientation, and time-areinstantly visible.The pictures show two parts of the

movie. At top, the stylized satellite-Earth system is seen from a positionfixed relative to Earth (thirty selectedframes are superimposed). The lowerpicture shows the satellite from aposition orbiting with it. This is anadvantage of computer movie-making:the second viewpoint required onlyrelatively minor program changes.The film was "reshot" several times

to show the effects of various stabiliz-ing parameters.

Bell Telephone LaboratoriesResearch and Development Unit of the Bell Systemn

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burden of proof. Whenexer a proposedrestrictioni is likely to cause social tuir-moil (as in the case of caffeine), xxe canwisely insist on placing a heavy burdenof proof on those who propose thechange. However. forbidding the irrIa-diation of foodt w ould CauLIS nlO sOcialldisruption. outside the n1arrow circle ofaI few industrics aInd research l,aora-tories. Here the burden of proof is stlre-loon tlhose xx ho sax, (ignoring soe ofthe cv idceuce) that food irraLliation is1(00 percent salfe. It xxotuld hc 11h 1rd(lol,ltO fLUtUI C generations to eucouraLic. orecen permit. the development of' a food-irr.adialtion industrx on the hasis ot thepreseult iIclusOix c' Ce ideIlCC.

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Transfer Experiments:A Plea for Tolerance

The letter by Nicholls et a!. ( 22Dec.) reporting the r-esults of prclimll-in,arx experimenlts on the transfer ofcharIctctristics tfi olmi onie oscilloscopc toallttlocte b\- Illealls of an. extract. pro- -

duced a comliotinlt IreLIctioll aoillgml,>llycolleagues: nanlelx that the letter xxasreallx a palrody. with intent to portl-raxbx analogi the intr-insic absurditx ofI-cenlt `LlggeTCstions thlat it is p-0ossileC totl-rallslllit nicmorv betxw een loweer orca-n11is bx tcchniqLueCS SUperficia}lly slilllarto those described b Nicholls. IshouldICI like to poillt ouLt tha1t it thIetechlliqLies and resLlts Ot tral.IllsfCl- cx-perimlellts bet eenl oscilloscopes areallill(gouS to those of trial-nsfer experi-ulellts bet ecu Plalaria. tllexrlare alsoaillallogoYUs to those ol trallster of gclleticcfllractcristics bet\\ cell Ph1(iclwio(c(( uitsdcescribed bx Al11o \N .aN (1). the actix e

c(I-lllonenlt tf xl\hiich xas sutbhsccuclltlxniden1tIfieCd as DNA bx Axerx \l adleod.atnd McC artv (2). 1-lihose e\perilmlelts,fLr frI-o11 heing allsurd. Ilaxe haid stuchifartr-reachillng cotsequeiices t1lat I lackaIrTOCaInCe tO SlIIlaIl iZe thelll.

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SCIENCE, 'VOL. 159

entist worthy of his chalk can give aquick and rigorous proof, based onrock-bottom fundamentals, that anyparticular idea, already known to beincorrect, is obviously, or even trivially,absurd. But the converse reasoning hasfailed in such an impressively largenumber of important cases, that itseems to be a relatively weak and un-convincing method of scholarly pro-cedure.

ARTHUR M. LESKBiochemical Sciences Program, FrickChemical Laboratory, PrincetonUniversity, Princeton, New Jersey

References

1. J. L. Alloway, J. Exp. Med. 55, 91 (1932);57, 265 (1933).

2. 0. T. Avery, C. M. MacLeod, M. McCarty,ibid. 79, 137 (1944).

Reciprocity in War

Are the "thirteen hundred fellows andactive members of the American Socio-logical Association" (22 Dec., p. 1553),also planning to send an open letter toHo Chi Minh, protesting the recentNorth Vietnamese massacre of Monta-gnard women and children with flame-throwers?

I urge them to do so, for it is ob-viously hypocritical to protest "thecontinued . . . killing of civilians" bythe United States and remain silentwhen the other side does the same thing,and deliberately at that. I think thesociologists should conduct an "orderly,phased withdrawal" from this sort ofadvocacy, lest they open their own"credibility gap."

JOHN M. BREWER293 Forest Road,Athens, Georgia 30601

Our Age of Elegance

I was pleased to note that, in theprogram for the recent AAAS meet-ing, female leaders of section meetingsand symposia were listed as Chairlady.It seems that, in spite of our slacksand miniskirts, all respect for woman-hood is not lost! However, in orderto forestall a demand from the othersex for equal rights, may I suggestthat at the 1968 meeting male leadersof section meetings and symposia belisted *as Chairgentleman.

RUTH S. BITTER707 Seventh Street,Niagara Falls, New York 143011 MARCH 1968

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Maxwell, secretary, IAI'SO; Gordon A.Macdonald, president, IAVCEI; andWilliam C. Ackeirniann, vice president,IASH.The 1 5th General Assembly1rwill be

held in 1971. Invitations were reccivedfromn India, RuLssia.l and Fratnce. AsFraance has indicalted its wxillintzness todefer its invitation ulntil 1975, theChoice will rcst on1lacyreement betxecnthe Othel two coLlItries.

In each of the foLr cities a receptionw5 as held bv the Amierican Delegationlfor the delea'ates flromii other landis.Three xverc r-eceptions hield itn hotels,the oitIh-tl in ZuL-ichX.was held in theformii ot at cruise oni Lake ZuLrich.

Thcrie were somle 250(0 per-sol.s inattendltance at the Assemblxly, aIboLut 600of wxhlim xwere ft-omi the Linitcd Staltes.

ITlie Unitecd States Natiolnal C'ommiiit-tee a-ind Deelcation SnfleredI aI ereatloss in the dleath of A. Nelsoni Sala -c,generail secretarv ot the American Geo-phxysica-l Union. He wx as stricken oin theliast dax of the Assenihlv (7 October)and dliecd on 12 Octobel in Zulirich.

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Calendar- of Events

National 'Meetings

Mlarch

10-12. Americani Soc. for AbrasiveMethods. Philadelphlia. Pa. (R. J. Mayer,ASAM. 330 S. WJells St., Chicago, Ill.60606)

10-14. Gas Turbine Conf.. Washington,D.C. (A. B. Conlin. Jr., Mleetings MIa-n-ager, 345 E. 47 St.. NessT York 10017)

10-15. American Soc. of Photogransi-metry American Congr. on SUrseying andMappingi. annual iltg., Waashington, D.C.(W. B. Oserstreet. 1819 Fransall AvenuieSilver Spring, Md. 2-0902)

11-12. Phonocardiography, AmericanCollege of Cardiology, Chicago, I11. (W. D.Nelligan. 9650 Rocks ille Pike, Watshing-ton, D.C. 20014)

11-13. American College of Surgeons,sectional mtg. for Doctors and Nurses,Williamsburg. Va. (Communications De-partmenit, 55 E. Erie St.. Chicago, Ill.60611 )

1 1-3. Nes Tools for Planning and Re-search Prograisiming, Commercial Chem-ical Dcvelopment Assoc., Inc. annual mtg.,New York. N.Y. (R. L. Chilenskas. Man-ager of Commercial Developmient NI & TChemicals Inc.. Ness York, N.Y. )

1]-13. Wlildlife Management Inst., 33rdnatural- resouLrces conf.. HoLuston, Tex.(Wildlife Management Inst., 709 WireBuilding, Washington. D.C. 20005)

11-14. Canaveral Council of Technical

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announcing

ESTTAR,IIES

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SC~IFNC-1. VOL. 159